using chrome cast to hack my network?

So I am being hacked by my soon to be ex husband and I can't figure out how he is doing it but this Chromecast 3655 is my old chrome cast that went missing and its always on as a choice in wifi networks and I've searched every computer high and low. Can anyone tell me if this is possible that he's using the chrome cast to spy on my computer and how do i get it off. This is a very serious question, he has constantly known everything I've ever written and I could never figure out how and now that I filed for divorce he is trying to get custody of our little girl. Help??